Administration of arginine plus growth hormone releasing hormone to evaluate growth hormone (GH) secretory status in children with GH deficiency.

BACKGROUND: Diagnosis of growth hormone deficiency (GHD) in childhood is usually based on growth hormone (GH) response to at least two provocative stimuli. The aim of this study was to determine whether sequential administration of arginine (Arg) plus GH releasing hormone (GHRH) could be a useful tool in evaluating GHD in children. METHODS: Thirty patients with short stature (mean age 9.0 years) with decreased growth rate were tested for GHD with Arg and the insulin tolerance test (ITT). Patients with confirmed GHD (peak GH <8 ng/ml) were subsequently tested with Arg + GHRH. RESULTS: Maximum GH stimulation for Arg and ITT was 6.3 (1.0-7.8) and 6.7 (0.5-7.7) ng/ml, respectively. Peak GH for the Arg + GHRH test was 36.3 (4.3-84.5) ng/ml and significantly different from the other provocative tests. Peak GH values for the three tests were not significantly correlated between tests or with clinical parameters. There were no significant differences in Arg + GHRH results between children with or without abnormal hypothalamic-pituitary MRI scans. CONCLUSION: Arg + GHRH gave higher GH levels than insulin or Arg alone. Because of the different causes of childhood GHD (hypothalamic and/or pituitary dysfunction), the Arg + GHRH test is unsuitable .for evaluating GHD and deciding whether GH replacement therapy is indicated.

Clinical evidence-based cutoff limits for GH stimulation tests in children with a backup of results with reference to mass spectrometry.

CONTEXT: Cutoff limits of GH stimulation tests to diagnose GH deficiency (GHD) in children and adolescents are not sufficiently validated by clinical studies due to discrepancies in the performance of GH immunoassays and lack of available study populations. OBJECTIVE: We aimed to establish new cutoff limits for GH stimulation tests based on clinical evidence and compared these immunoassay-based values with an antibody-independent mass spectrometric method. DESIGN AND SETTING: In a retrospective study, GH cutoff limits for eight different immunoassays and isotope dilution mass spectrometry (ID-MS) were calculated from hGH peak concentrations of short-statured children with and without GHD. PATIENTS: We compared the serum GH peak concentrations at GH stimulation test of 52 short-statured children and adolescents, who have normal GH secretion at initial workup and normal growth in the follow-up, with the serum GH peak concentrations of 44 GHD patients in the same age range, in order to optimize the cutoff limit calculation. RESULTS: Discriminant analysis of re-measured GH led to a new cutoff limit of 7.09 µg/l using the iSYS assay (IDS) and the limits for the other seven hGH assays varied between 4.32 and 7.77 µg/l. For ID-MS, cutoffs of 5.48 µg/l (22k GH) and 7.43 µg/l (total GH) were ascertained. CONCLUSION: The establishment of method-specific clinical evidence-based GH cutoff limits is of importance to ensure adequate clinical diagnosis and treatment of children and adolescents with GHD. ID-MS may become an important tool for providing both reliable and sustainable SI traceability of GH measurements in the future.

An insulin-like growth factor-I receptor defect associated with short stature and impaired carbohydrate homeostasis in an Italian pedigree.

BACKGROUND: Mutations in the insulin-like growth factor-I (IGF-I) receptor (IGF1R) have been associated with prenatal and postnatal growth retardation. However, little is known about potential effects of mutations in the IGF1R on carbohydrate homeostasis. METHODS: We investigated clinical, endocrine and metabolic parameters in four family members carrying a novel IGF1R mutation (p.Tyr387X): an 18-year-old male (index case), his sister and two paternal aunts. RESULTS: All family members showed a variable degree of impairment in prenatal growth, with birth weight standard deviation scores (SDS) between -1.65 and -2.37 and birth length SDS between -1.78 and -3.08. Their postnatal growth was also impaired, with height SDS between -1.75 and -4.86. The index case presented high IGF-I levels during childhood and adolescence and delayed bone age. The index case and his two paternal aunts had impaired glucose tolerance (IGT) associated with a variable degree of alterations in insulin sensitivity and secretion. In contrast, the index case's sister, who had had IGT during pregnancy, showed normal glucose metabolism but reduced insulin sensitivity. CONCLUSION: This is the first study showing an association between a novel IGF1R mutation and a variable degree of alterations in prenatal and postnatal growth and in carbohydrate metabolism.

A novel GNAS1 mutation in a German family with Albright's hereditary osteodystrophy.

Albright's hereditary osteodystrophy (AHO) is an inherited disorder and results from heterozygous loss of function mutation within the human G (s)α gene (GNAS1). AHO appears in two phenotypes, that may occur within the same family. Pseudohypoparathyroidism type Ia (PHP Ia) comprises the clinical features of AHO associated with parathyroid hormone (PTH) resistance while pseudo-pseudohypoparathyroidism (PPHP) includes AHO features without PTH resistance. In the present study we report a mother and a daughter with PPHP and PHP Ia respectively. The 13 exons of GNAS1 were analysed by PCR and direct sequencing. We identified a heterozygous missense mutation in exon 1. This novel mutation results in a stop at codon 35 and a truncated non-functional GNAS1 protein.

Effects of dehydroepiandrosterone therapy on pubic hair growth and psychological well-being in adolescent girls and young women with central adrenal insufficiency: a double-blind, randomized, placebo-controlled phase III trial.

CONTEXT AND OBJECTIVE: The efficacy of oral dehydroepiandrosterone (DHEA) in the treatment of atrichia pubis and psychological distress in young females with central adrenal insufficiency is unknown. Our study aimed to evaluate this therapy. DESIGN AND PATIENTS: A total of 23 young females (mean age 18 yr, range 13-25) was enrolled in a double-blind randomized placebo-controlled trial. Inclusion criteria were ACTH deficiency plus two or more additional pituitary deficiencies, serum DHEA less than 400 ng/ml, and pubertal stage more than B2. Exclusion criteria were cerebral radiation with more than 30 Gy, tumor remission less than 1 yr, amaurosis, hypothalamic obesity, psychiatric disorders, and unstable hormone medication. INTERVENTION: Patients were randomized to placebo (n = 12) or 25 mg HPLC-purified DHEA/d (n = 11) orally for 12 months after stratification into a nontumor (n = 7) and a tumor group (n = 16). MAIN OUTCOME MEASURES: Clinical scoring of pubic hair stage was performed at 0, 6, and 12 months (primary endpoint), and psychometrical evaluation (Symptom Check-List-90-R and the Centre for Epidemiological Studies-Depression Scale) at 0 and 12 months (secondary endpoint). Androgen levels and safety parameters were measured at 0, 6, and 12 months; 24-h androgen urinary excretion rates were calculated at 0 and 12 months. RESULTS: In the placebo group, four patients dropped out because of recurrence of craniopharyngioma, manifestation of type 1 diabetes, and change of residence (n = 2); in the DHEA group, one patient dropped out because of recurrent anxiety attacks. DHEA substitution resulted in normalization of DHEA sulfate and androstanediol glucuronide morning serum levels 2 h after drug intake (P < 0.006), and of its 24 h urinary metabolite levels (P < 0.0001), placebo had no effect. Morning serum levels of androstenedione increased in the DHEA group (P < 0.02) but did not normalize. The DHEA group exhibited significant progress in pubic hair growth from Tanner stage I-III to II-V (mean: +1.5 stages), whereas the placebo group did not (relative risk 0.138; 95% confidence interval 0.021-0.914; P = 0.0046). Importantly, eight of the 10 Symptom Check-List-90-R scores, including those for depression, anxiety, and interpersonal sensitivity, and the global severity index improved in the DHEA group in comparison to the placebo group (P < 0.048). DHEA was well tolerated. CONCLUSIONS: In adolescent girls with central adrenal insufficiency, daily replacement with 25 mg DHEA orally is beneficial: atrichia pubis vanishes, and psychological well-being improves significantly.

Reference intervals for TSH and thyroid hormones are mainly affected by age, body mass index and number of blood leucocytes, but hardly by gender and thyroid autoantibodies during the first decades of life.

OBJECTIVES: The purpose of our study was to establish reference intervals for thyroid function tests in children and adolescents and to identify factors that may influence the limits of these intervals. METHODS: TSH, FT3, FT4, T3, T4, t-uptake, TPO-antibody (TPO-Ab) and TG-antibody (TG-Ab) levels were determined in blood of 1004 infants, children and adolescents by the Elecsys system (Roche). RESULTS: A distinct overall age-dependent decrease of analyte levels was found for all parameters investigated. Puberty was accompanied by an increase of TSH, FT3 and T3 levels. Results of T4 and t-uptake were significantly higher in girls compared to boys. The exclusion of children with increased TPO-Ab and TG-Ab had no significant effect on the limits of the reference interval. We found that besides age, BMI-SDS but also white blood cells count and gender played a role in the prediction of analyte variation. CONCLUSIONS: Covariates like BMI-SDS and white blood cell count should be taken into consideration when interpreting TSH and thyroid hormone measurements as well whereas gender and TPO-Ab or TG-Ab play a minor role.